Running in the horizontal plane with a multi-modal dynamical robot

As the use of mobile robots expands to more diverse and challenging environments, improved mobility methods are required to provide these platforms with the ability to reliably negotiate these terrains. In this paper, we investigate SCARAB, a quadrupedal platform designed to rapidly traverse level, vertical, and inclined surfaces. This study extends previous work in which SCARAB's climbing performance was analyzed to demonstrate its ability to run effectively on level ground. We detail several modifications made to the platform to improve its capacity to both climb and run. This updated platform was used to investigate the influence of leg configuration and leg phasing on running performance and shows that SCARAB is able to run at speeds upward of 40cms^-1. Furthermore, analysis of the dynamic characteristics shows similarity between those of the robot and the Lateral Leg Spring model, particularly for configurations that produce the highest running speeds. These results make SCARAB the first platform to effectively demonstrate horizontal plane dynamics quantitatively similar to this model, as well as the first to utilize two distinct dynamical locomotion modalities.